Watercare’s Tunnel Boring Machine passes halfway mark in Queen Street’s $115m wastewater upgrade

Watercare’s micro-tunnel boring machine (m-TBM) yesterday broke through into a shaft at the intersection of Wellesley Street and Queen Street, passing the halfway point in its 600-metre journey down Queen Street to lay a new wastewater pipe as part of the Midtown Wastewater Diversion project.

The 1.3-metre diameter cutterhead of the m-TBM cut through the walls of the Wellesley Street shaft at lunchtime, almost two months after leaving its starting point in Mayoral Drive.

Watercare delivery manager David Heinrich says the breakthrough is an important milestone in the $115m wastewater water upgrade for the city centre: “There were a few cheers from construction crew who watched as the cutterhead appeared through the shaft wall. Hats off to the skills of the project team for ensuring the machine arrived safely and on target.”

The new wastewater pipe will connect to the Ōrākei Main Sewer and capture flows from the city centre. The project will reduce wet- weather overflows into the Waitematā Harbour, improve the resilience of the local wastewater network, and allow for growth.

Once the m-TBM has been cleaned, the cutterhead will be switched to enable it to cut through hard basalt rock for the final section of the journey: from the Wellesley shaft to Victoria Street East.  It will resume tunnelling early next week.

The second tunnelling drive will be shorter: 217 metres, with the operation being carried out from the Mayoral Drive shaft. Hard basalt rock conditions mean tunnelling will be slower. It is due to finish in October.  

Photo: The cutterhead belonging to Watercare’s micro-Tunnel Boring Machine is clearly visible after emerging through a shaft in Wellesley Street at the junction with Queen Street.

Stage two of works is in design and will involve laying new wastewater pipes from Vincent Street to Greys Avenue carpark. The work is due to be completed in 2027.

“Great care is being taken to minimise disruption for residents and local businesses while the work takes place,” Heinrich says.

“We’ve installed solid fencing around our sites to reduce noise and dust, and we’ve provided easy pedestrian access and clear signage to let people know businesses are still operating.”

The project is part of Watercare’s $13.8b infrastructure investment programme being delivered over the next decade to enable new housing, improve the reliability of services and protect the environment.

The project forms part of the Auckland Council group’s midtown regeneration programme which is transforming the streets, spaces and underground infrastructure in midtown so that it’s ready for when the City Rail Link opens and brings many more people into the city centre.

Stage two of works is in design and will involve laying new wastewater pipes from Vincent Street to Greys Avenue carpark. That work is due to be completed in 2027.

The project is part of Watercare’s $13.8b infrastructure investment programme being delivered over the next decade to enable new housing, improve the reliability of services, and protect the environment.